Karyotype Webquest
Name: ____________________
Use the following websites to learn about karyotyping and prenatal testing:
I. ​Prenatal Testing​: Real World Connection
http://americanpregnancy.org/prenatal-testing/
1. Click and read through the information on “Amniocentesis” and “Chorionic Villus Sampling”
a. Compare/Contrast the two procedures:
2. Click on the “Quad Screen”
a. Does every woman undergo the quad screen? If not, then when is it necessary?
II. ​Karyotyping
http://learn.genetics.utah.edu/content/chromosomes/
1. Click on “How do scientists read chromosomes”
a. Identify 3 key features that scientists use to identify the similarities and differences of the
chromosomes. ​Size, Banding pattern, and Centromere position
b. What are centromeres for?​ ​required for chromosome separation during cell division
c. Differentiate between acrocentric, metacentric, and submetracentric chromosomes. ​In
metacentric the centromere lies near the center of the chromosome. In
submetacentric have a centromere that is off-center. In acrocentric the
centromere is very near one end.
2. Click on “Make a Karyotype”
a. Is the karyotype of a male or female? How do you know? Male because there’s X and Y
chromosomes
3. Click on “Using Karyotypes to diagnose genetic disorders”.
a. ​A regular human cell has _​46​__ chromosomes: _​44​__ autosomes, which come in pairs, and _​2​__
sex chromosomes, which specify gender (XX for female and XY for male).
The pairs of autosomes are called "____________​homologous ​____________ chromosomes." One
of each pair came from mom and the other came from dad. Homologous chromosomes have all of the
same genes arranged in the same order, but with slight differences in the DNA sequences of the genes.
b. Identify 3 conditions that can develop from having too many or too few chromosomes, missing pieces
of chromosomes, or mixed up pieces of chromosomes? ​aneuploidy,
monosomy, and trisomy
c. Differentiate between terminal and interstitial deletions.​Terminal
deletion is the loss of the
end of a chromosome. An interstitial deletion results after two breaks are induced.
d. What is a translocation?​a
chromosomal segment is moved from one position to
another
e. Differentiate between reciprocal and Robertsonian translocations.​Reciprocal
translocations are
usually an exchange of material between non-homologous chromosomes. ​ Non-reciprocal
translocations are a one-way transfer of a chromosomal segment to another chromosome
III. ​Analyzing Karyotypes
*Use the karyotypes on the next few pages to complete the information in Table 1. Use the internet to research
the chromosomal abnormalities.
Table 1
Karyotype
#
Gender
# of autosomes
# of sex
chromosomes
Normal or Abnormal
(If abnormal, identify disorder and
symptoms)
1
2
3
4
5
6
7
8
IV. ​Final Reflection
1. What do you think the relationship is between chromosomal abnormalities and age?
2. What do you think could be done to minimize the risk of having a child with a chromosomal abnormality?